There are situations where a color image needs to be converted into a gray scale image. Often a picture can have more impact as a black and white image. There are software programs that can automatically convert a color image into a gray scale image. One typical approach for such automated conversion averages the data of the Red, Green and Blue channels at each pixel of the color image to obtain the gray scale intensity. Other approaches evaluate a luminance measure from the color components of a color space (e.g., a Red, Green and Blue (RGB) color space) to determine the gray scale intensity. For example, the RGB values of a pixel can be used to compute the luminance component of a Hue, Saturation and Luminance (HSL) color space; the luminance component can then be used as the gray scale intensity and assigned to the RGB channels of the pixel. Such traditional methods of automated conversion typically do not generate aesthetically pleasing gray scale images.
Some software programs allow a user to choose the weight of each of the color channels for computing the gray scale intensity. After a user specifies a set of weights for different color channels, the software programs convert a color image into a gray scale image based on the user specified weights. Thus, a user may manually adjust the weight for each of the color channels to create different gray scale images for inspection and for comparison. Through manual adjustment the weights for different channels and visual inspection of the resulting gray scale images, a user can create a customized gray scale image according to the artistic taste of the user. Such an approach is suitable for users who have the time, interest, and knowledge in customizing the gray scale image. Although an experienced user may produce the desired result quickly, a typical user may find the trial-and-error process time consuming.